Apparatus for truing up tubular bodies



AJune 6, 1944. c. E. MURPHY 2,350,410 l APPARATUS FOR TRUING U-P TUBULAR BODIES lFiled Nov. 25, 1940 2 sheets-smet 1 ATTORNEY.

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June 6; 1944.

C. E. MURPHY APPARATUS FOR TRUING UP TUBULAR BODIES 2 Sheets-Sheet 2 Filed Nov. 25 1940 ATTORNEY Patented June 6, 1944 APPARATUS FOR TR BODI UING UP TUBULAR Chalmer E. Murphy, Cleveland Heights, Ohio, as-

signor to Porcelain Steels, Inc., Cleveland, Ohio, a corporation of Ohio Application November 25, 1940, serial N0. 367,077

(ci. s-so) 6 Claims.

This invention relates to metal-working machines and methods.

While my invention has other uses it is particularly applicable to the process of making enamel-coated tanks, illustrative of which is the domestic hot water will be illustrated plied to that use. tank is illustrated and and

supply tank and my invention described herein 'as ap- A construction of hot Water described in co-pending applications filed by me and to be referred to hereinafter and this construction will therefor herein be brielly described. The tank comprises a cylindrical tubul ar body of sheet s-teel to the opposite ends of which heads are attached. `The body and the headsare coated inside or inside and outside With vitreous enamel, that is to say,

with enamel fired and fused from dried enamel slip; and the he tion to the body ads are attached in sealed relaafter enameling. Such tanks in use contain hot water under pressure and at the time of manufacturing them the manufacturer must greater internal pressure to test them under much be able to guarantee for them long useful leak-proof and pressureproof life. brittle.

The enamel coat is glass-like and Any deformation of or bending' of the metal of the walls of the tank after assembling,

such as might be caused nal pressure in use, Will by the applied intercrack the enamel. The

main purpose of the enamel coat is to prevent contact of the hot water metal of the wall which rodes the Wall, and in a time perfcrates the Wall which ends the useful life in the tank with the as is well-known correlatively short period of and produces a leak of the tank; and if a crack develops in the inside enamel Vcoat it Will expose the metal of the action.

wall to the corrosive Pressure in the tank may deform the walls of the tank and crack the If the heads are not sem sure will deform them enamel in several Ways. i-spherical in form, presrtoward more nearly true be acceptably and econ omically prevented by making the heads of sufficiently thick material.

But to make the main tank of such thick metal cylindrical body of the would raise the cost of the tank to a commercially prohibitive gure.

The -body therefor mus thin metal and if there portions thereon, or if it form to a considerable d t be made of relatively are V,any flat or planar is out of true cylindrical egree, or if there are any curved portions which tend to be straightened out by the longitudinal forces thereon exerted by the internal pressure on the opposite heads, such portions will 'deforin or bend and crackthe enamel.

Also when high rtest pressure is Aused and the body wall is bent, the portions of the body 'midway between the heads Vbends or bulges outwardly, relative to portions more nearly adjacent the heads and this lcracks the enamel.

If the heads are attached to the body ends before enameling, making of the tank a closed container, dilliculties are encountered in obtaining a complete and solid coat oi enamel because free circulation of oxygen-containing air over the surfaces While the slip is being dried and while the dried slip is being formed is prevented. For this reason I prefer to form the body and the heads separately and enamel them separately and-then attach the heads to the body. .Also by making the heads and body separately they may be completely inspected before enameling and any roughnesses on the surfaces can be removed before enameling. The preferred means for attaching the heads vcomprises the use of a circular series of bolt Vdevices and it is therefor desirable when making the bodies in quantities independently of the heads, for the bodies `to be substantially of uniform diameter.

The present invention relates more particularly to a machine and method for truing up the body before enameling it to make it of circular cross section; and to remove any planar or out of round portions which might be deformed and cause cracking of the enamel by internal pressure; and to remove unequal strains in the metal which might cause the body wall to be deformed when heated during vthe enameling process.

The invention comprises means to mechanically expand the tubular body Wall on all diameters equally over its entire length and including,

. if preferred, the metal head-'attaching rings and the flanges referred to above, to true the same, and suiliciently to set the metal in its vexpanded condition, and to attain a predetermined diameter of all of a number `o f like bodies to render them readily assemblable and interchangeable with the heads.

It is among theo for,

To. provide an improved hot-Water tank body constructionY Worked in an improved manner to retain unbroken a coat of vitreous enamel when subjected to internal lpressure. in use.

-To provide an improved machine and V'method bjects of' the invention theremachine and methodY of for working the metal wall of the tubular tank body to cause it to retain its form and not to be deformed by internal pressure therein so that an enamel coat thereon will not be cracked by the pressure.

To provide an improved method and means for working the metal of a metal head-attaching ring at the end of a tubular tank body and/ or a flange formed over the ring.

To provide an improved machine and method for making the tubular metal body wall of a hot Water or like tank having means for attaching heads to the ends thereof.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawings in Which,

Fig. 1 is a view with parts broken away of a. tank to the makingof the parts of which the machine and method Y may be applied; t Y

Fig. 2 is a fragmentary longitudinal sectional view to enlarged scale of a part of the tank of Fig. 1 illustrating one means for attaching the heads thereof to the body thereof;

Fig.l 3 is aview inlongitudinal section, with parts broken away, of the body of the tank of Fig. 1, and illustrating a part of the method of making it;

Fig. 4 is a viewy in longitudinal section and in some respects diagrammatic, illustrating 'a machine by which a metal working operation may be performed on a tank body such as that shown inFigs.2and 3; A 4 Fig. 5 is a cross-sectional .view taken from the plane 5-5 of Fig.` 4; ,A Fig. 6 and Fig.r'7 are fragmentary viewsjsimilar to corresponding parts of Fig. 4 illustrating modiembodying my invention v fications.

In Figs. 1 to 3 of the drawings, a tank'is illustrated comprisinga tubular cylindrical body I, and upper and lower heads Zand 3. Any desired number of conduits 4-4 may beprovided for communication with the interior of the tank, and, if desired, conduits not shown may be provided communicating with the tank interior through the wall of the body I.'

The preferred construction ofj'the bodyV |is' shown in Figs. 2 and' 3, and comprises metal rings ends,and ,flanges 6-6 bent outwardly and coined overV the rings 5, the end portions of the wall being shown in dotted line at 6AL before the flanges are formed.' 'i

The body in thenrst instance, andbefore'the f flanges Gare formed, or the ringsv 5fapplied, may be made by rolling a sheet of metal into generally tubular form and'welding abutting edgesthereof togetheralong a seam indicated at l, which seam is preferably vperformed by the flash welding process and the flash fin tooled` off down tol the solid metal to facilitate the formingof an enamel coat thereover. K f l t Y The metal of the body I', is then worked by the', this application to be presently described, and the rings and flanges being provided either before A working operation is performed, as shown in Fig. 2, a coat `of vitreous enamel 8 is formed preferably both von the inside and outside and over the fiange 6 and ring y5. .The heads,sich` as the head 2 vofA Fig. 2,v are then mounted rori thel ends of' the body.` Preferably theseY headsicmpri'se an annular planar portion Q opposite the V*flange n 6,

115 tion Serial Number 5-5 surroundingl the body, inwardly of its or after metalVV and a skirt I radi lly outwardly of the flange 6 and ring 5, and coated with vitreous enamel I I covering the head, the planar portion and the skirt.

In the space between the skirt IIB and the ring 5 and flange 6, bolts I2 are projected downwardly, through suitable perforations in the head and threaded through plates or washers I3 bridging the skirt periphery and ring 5, to exert a clamping l0 action upon a sealing gasket I4 between the head and the ange B to effect a liquid-tight and pressure-proof seal ,thereat YAnother construction for attaching the heads to such a body is shown in my pending applica- 339,753 filed June l0, 1940, for

improvements in Enamelled hot water tanks and involving a flange and a ring as referred to above. In the forming the body I and in applying the ring 5, for example by tack or spot welding it to the body, and in forming the flange 6, these parts may become out of round transversely; and particularly the body wall I' may have relatively at portions thereon; and even if they were carefully made so as to be'circular in cross-section, there 5 may be strains in the metal which, when the metal is heated to form the enamel coat, would cause these parts to go out of round or to assume relatively fiat shape in portions thereof. A machine and method will now Ybe described by 0 which these irregularities may be removed not only in intermediate portions of the body longitudinally, but also in the rings and flanges if desired; This machine and method not only removes these irregularities which might result in cracking of the enamel when the finished tank is subjected to internal pressure as referred to, but, as'the result of causing a quantity of lsuch bodies to be all of substantially the same diameter `and circular form, the attachment of the heads is 4( facilitated and makes separately made bodies interchangeable with separately made heads.

Referring to Figs. 4 and 5 I have shown at l5 a main frame or base having in the upper portion thereof an inwardly extending flange IG providing 45. aV large opening I'I. A plurality of angularly spaced radial grooves I8-I8 are provided in the upper partA of the flange I6.

An expanding tool or mandrel is provided in the upper central part of the machine and comprises a plurality of upwardly elongated expanders I9--I9 disposed in a cylindrical series around a vertical Yaxis the radially outer portions 20-20 thereof defining substantially a cylinder. At

their lower ends the expanders I9 have outwardly radially extending feet 2I--2I thereon, arranged to rest in and be supported in and to slide radially in the grooves I 8`. The feet 2| are provided with radial slots 49 through which bolts 48 are loosely projected and threaded into the flange I6 t'o hold the expanders upright, but permitting `them to move radially.

The outward radial movement of the feet 2I inthe grooves I8, and therefore of the lower ends Iof the expanders v19-I9, is limited and 35 stopped by their engagement with the ends 22 of the grooves.v Corresp'ondingly the outward radial movement of the upperends of the expanders I9-I9 is stopped byY a ring .23 resting and float# ing upon shoulders 2li-424 on theupper ends of the expanders, the shoulders being formed by notches, therein, the side walls 25-'25 ofthe notchesbe'ing engageable fwith vthe ring.

"The expandersIS-f-WS normally are moved to and held inthleir radially inner positions illus- (5 trated, by'spririgs.26;..26 4abutting at their inner ends upon the feet 2|-2I and abutting Vat their outer ends upon the main frame or base, the main frame for this purpose extending upwardly as at 2'! beyond the grooves I8 and having recesses 28 to receive the springs.

On the upper and lower inner confronting portions of the expanders I9-I9 they are provided respectively with inclined preferably conical faces 29-29 and 39-30 as shown in Fig. 4. An upper expanding cone 3| is projected downwardly into the cylindrical series of expanders |9-|9, and engages the faces 29, and a lower expanding cone 32 similarly engages the faces 30.

The upper cone 3| is connected by means of a piston rod 33 with a piston 34 in a fluid pressure cylinder 25, the piston rod 33 extending through the lower cone 32. The lower cone 32 is connected to the wall of the cylinder 35 preferably by means of an annular flange 36 on the lower cone bolted to the cylinder.

The cylinder 35 may rest upon a support 31 on the lower part of the frame in its normal or unactuated position.

The piston rod 33 passing through the cone 32 may be sealed against escape of pressure from the cylinder 35 by a packing gland construction 38.

Conduit connections 38 and 39 are provided to introduce fluid pressure to the cylinder 35 above or below the piston 34 and to exhaust it from below or above the piston respectively. As shown diagrammatically the conduits 38 and 33 lead to a valve device 49 having connected thereto a pressure supply line 4| and an exhaust line 42.

The construction of this valve constitutes no essential parts of the present invention and may be any well-known valve for the purpose. The valve diagrammatically shown comprises a handle 43, and upon moving the handle in one direction, say toward the right, iiuid pressure is admitted from the supply line 4| to the conduit 38 supplying pressure above the piston 34 and exhaustng pressure from below the piston and out by the conduit 39 to the exhaust 42; and upon moving the handle in the other direction pressure above the piston is exhausted and pressure below the piston is applied to the cylinder 35.

The tank body comprising the body I the rings 5 and the flanges 6 is shown in Fig. 4 telescoped over the expanders I9 in position to be worked as described above, and for this purpose the flange 6 may rest upon the feet 2|.

In order that the expander may work bodies of diierent lengths, the expanders I9 are made long enough to extent somewhat over one-half of the length of the longest body to be worked.

yIn the operation thus far described, the valve 43 is moved to cause the piston 34 to move upwardly and raise the cone 3| and to cause the cylinder 35 to move downwardly and lower the cone 32. 'Ihe springs 26 move the expanders |9-`| 9 inwardly to engage the cones.

The body is then telescoped downwardly over the expanders |9 into the position illustrated. The ring 23 at all times is inwardly of and clears the inner wall of the body I. The valve handle 43 is then moved to admit pressure to the 4upper side of the piston cylinder 34, the` pressure acting to move the piston and the cone 3| downwardly and the cylinder 35 and the cone 32 upwardly. The cones 3| and 32 reacting upon the inclined faces 29 and 39 expand the expanders |9|9 radially outwardly and this goes on until the feet 2| engage and are stopped upon the ends 22 of the grooves 8, and until the notch walls 25 engage the ring 23 beyond which positions the 3 expanders as will be apparent cannot be moved.

After the operation thus performed is completed, the valve handle 43 is moved to exhaust pressure from above the piston 34 and to apply pressure below it which moves the cone 3| upwardly and the vcone 32 downwardly to relieve the expanding pressure from the expanders 'IS-*I9 and they are returned to their normal positions by the springs 26.

When the cones 3| and 32 are moved as described to exert their expanding pressure, one of them may move first followed by movement of the other; and similarly when the uid pressure is released to return them one of the cones may move before the other. In some cases when the pressure between the cones and the expanders I9 is released, the cylinder 35 may be suddenly projected downwardly and its downward movement will be stopped on the support 31. In other cases, the cone 3| may jump upwardly with a quick movement, and to limit this movement, a plate 44 may be provided resting loosely on the upper end of the cone 3| and having bolts 45 embraced by slots 46, and the plate will strike upon the heads of the bolts, and stop movement of the cones 3|, the bolts being screwed into the upper ends of the expanders l S-S. If the cone is pulled inwardly beyond the ends of the expanders, the plate 44 will be deposited on 'the ends of the expanders. Similarly at the time of such quick movement, the expanders I9 may tend to move inwardly with a quick or jumping movement, but they are stabilized by the bolts 48.

After one-half or more of the body has thus been worked, and after the pressure has been removed, the body is withdrawn from the expanders I 9 and turned end for end and the operation repeated on the other half portion.

The -outer diameter 20 of the assembly of expanders |9-I9 is such that the body I will telesc'ope thereover with suitable clearance for a body of approximate pre-selected diameter attained in the making of the body; and the extent of movement permitted by the expanders I9 in moving to their definitely stopped positions as described above, is pre-determined to expand the body wall, rings 5, and flanges 6, a predetermined amount. This amount is pre-determined to be suicient to stretch the metal of the wall slightly beyond its elastic limit and therefor to set the metal in its stretched condition so that the worked and stretched body is made permanently of larger diameter than when originally made. Besides this as will be obvious it is rendered subr stantially circular in cross-section at all parts and to this latter end, the surfaces of the expanders I9 which engage the inner wall of the body may be s'o formed that the cylinder 20 defined thereby is'a true cylinder after the radially outward movement of the expanders |9-|9 has taken place. Thus any planar portions or out of round portions of the body ring or ange are removed by this metal-working operation.

The stretching of the metal beyond its elastic limit also precludes any possibility that internal pressure even a high-testing pressure will further expand the body and crack an enamel coat thereon during testing, the thickness of the metal of the wall of the body I being pre-selected to have a strength to resist expansion beyond its stretched condition by any testing'pressure employed; this being desirable because the ends of the body are reinforced by the flanges 6 and rings 5, the longitudinally central part of the wall therefore being the weakest and most liable to be enjoyed.

bulge outwardly under internal pressure and crack an enamel coat thereon. Y When the body is longer than the expandersand as shown in Fig. 4, and if the maximum amount of stretch in the body wall is to be eectedit may be desirable to relieve or taper off the upper ends of the expanders asV indicated in dotted line .atA 50 to avoid producing a shoulderin the bodywall, which may not all be removable by the stretching operation on the otherend vportion of v,the body when itis reversed on the'expandersrz- In Fig.V 4 I have illustrated and described above a means rfor stopping andlimitingthe outward expanding movement of the expanders IS-MIQ. In Figs. 6 and 7 I have shown for this purpose which is adjustable. In Fig. '7, a plurality of metal washers EI-EI in thenature of shims are telescoped over the lower cone 32 and rest upon the cone flange 36. When the cone 32 moves upwardly-in the expanding direction, these shims engage the lower ends of the expanders I@ and positively stop -furtherqmovement of the cone. /In Fig. `6, the upper cone 3l, in this case Sia, is made longer and a plurality of plates or shims 52-52 are placed upon the upper end of the cone secured thereon4 between the cone and a heavy plate 53 by bolts v54. When the upper cone 3IA moves 52 are stopped upon the upperrends oftheexpanders lil- KLV By changing the number or thickness ofthe shims 5lV and/or52 ,the expansion movement of theexpa ders-IS-Idrwill be definitely stopped by positively stoppingthe movement of the cones thereby. Y

Figs. 6 and 7 aisolinustrate that the bodyvieu l to be expanded may have this operation Vperformed onY it before the rings 5 and flangesi have been provided. thereon; and also illustrate that the expanders 19K-i9 kmay be 1911s enough to stretch the entire bodyfrom end ,to 'pend Aat one operation. y Y v It is after the body hasbeen operated upon asdescribed that it is enamel coated as ,referred to and as indicated in Fig. 3, the purposeof the metal-working operation described being as referred to above to insure against enamel cracking in thev finished tank and to'facilitate the another. means y downwardly the-plates f exerting the same stretching pressure on the wall as each of the others. It will be observed also that the body being worked, oats on the machine, being free toV move laterally so that it is at all times aligned co-axially with the expanders. Which further insures that all parts of the Ywall ofl the body will be equally stretched.

Myjinvention' is not limited to 'the exact details VVof Yconstruction of the machine above-describedror of the steps of the method which it performs. vChanges and modifications kmay be madewithin the spirit of my invention without sacrificing its Vadvantages and my invention is comprehensive of all, such changes and modifications which come withinY the scope of the appended claims. v Y .1I claim: y Y Y 1. In a machine kfor working the metal of a tubular metal body, a main frame; a plurality of radially extending guide ways on the frame; a plurality of parallel, elongated expander elements disposed in a cylindrical series around an axis and having feet respectively slideable in the guide ways; springs yieldingly constraining the feet and'their associated expander `elements to move toward the axis; the expander elements rhaving faces defining a cylindrical surface;YA cone elements projected axially into the series of expander elements at each end thereof; means to force the cone elements into the series of expander elements to move them outwardly radially, comprising a cylinder connected to one cone element and a piston in the cylinder and a piston rodV connected vto the other cone element and extending to the piston through the one cone element;rmeans to communicate fluid pressure tothe cylinder on one side of the piston to move the cone elements toward each other to spread the expander elements apart, and to communicate fluid pressure to the other side of the piston to move the cone elements toward each other to relieve the force vfrom the expander l elements.

attaching of the heads and to render a number Y of bodies interchangeableY with a number of; heads whereby economies of manufacturermay As illustrative of 4'the quantitative expansion which may with advantages be utilized, Vif fity beY desired to make a tank the'diameter' of .whichl is 12 inches, itrnay initially be mately a diameter `of 11% inchesV and then ex.- panded 1/4 inch on the diameter to bring it to the 12 inches. An incidental economy is effected thereby. The originalY body will in circumfer-A ence be approximately 1-85 of an inch lessin cir.-

cumferencethan the finished Abody andltherefor Ya sheet of steel 1% of an inch narrower may be used in making it. vWhile of material oneach tank, when suchv tanks are made in large quantities thelsaving is appreciable. Y

made of. approxe this is a small saving In the machine Yas illustrated and* described l above, it vwill be observed that noflateralj guidesA are provided for either-the cone 3l Yor the cone 32 or the'pistonandcylindersd-fl, theseparts, being free to neatlaterally Y.during operation;v and likewise'. the expander's .fig-Id are free to float'. laterally. By i exerted by all'.of/.theexp'anders VIfigon thervcvall e or the body will'bev ec lualized.'Y each expander 1 9@ Y 2. In a machine for working the metal of a tubular vvtank body, a 'main frame; a plurality of .radially extending guide ways on rthe frame; a plurality Vof parallel, elongated expander ele- -ments disposed in acylin'drical series around an axis and having feet respectively slideable in the guide ways; springs yieldinglyy constraining the feet and their associated expander elements to move toward the axis; the expander elements having faces defining a cylindrical surface; cone elements projected axiallyv into the seriesof expander' elements at eachend thereof; `meansto i'crcc'tiecone elements into the series of expander elements to move them outwardly radially, comprising a cylinder connected to one cone elemeritand a piston in the cylinder connected to the other cone element; means to communicate fluid pressure Vrtothe cylinder on one side of the piston Tto move the cone elements toward each other to spreadr the expander elementsapart,

andftocorrirnunicatefluidpressure to the other side:;of thepiston to move the cone elements toward each other to relieve the'force from the expander elements; and the expander elements being 4free to'move radially independently of eachother andiioati'ngly Vsupporting the cone elementaand the cone elements oatingly supporting the piston and cylinder.

,3. In -a machine forworking the metal of a tubular metal body, a ,main frame; a plurality of radiallyextending guide ways on the frame;

a plurality otparallel, elongated expander ele-ff ments disposed in a cylindrical series around an axis and having feet respectively slideable in the guide ways; springs yieldingly constraining the feet and their associated expander elements to move toward the axis; the expander elements having faces defining a cylindrical surface; cone elements projected axially into the series of expander elements at each end thereof; means to force the cone elements into the series of expander elements to move them outwardly radially, comprising a cylinder connected to one cone element and a piston in the cylinder and a piston rod connected to the other cone element and extending to the piston through the one cone element; means to communicate fluid pressure to the cylinder on one side of the piston to move the cone elements toward each other to spread the expander elements apart, and to communicate Huid pressure to the other side of the piston to move the cone elements toward each other to relieve the force from the expander elements; and means to limit outward expanding movement of the expander elements.

4. In a machine for expanding and truing up to cylindrical form the metal of a tubular metal body; a frame; a plurality of elongated expander elements disposed in a generally cylindrical series around an axis, and having outer surfaces defining a cylinder, disposed for telescoping of the body thereover; means supporting the expander elements on the frame and guiding them for movement radially toward and from the axis, and independently of each other; stop means for limiting radial movement of the expander elements away from the axis; a pair of tapered wedging elements disposed within the opposite ends respectively of the cylindrical series of expander elements, for moving the expander elements away from the axis upon movement of the wedging elements axially in opposite directions; a uid pressure cylinder and a piston therein for moving the wedging elements; the cylinder being connected to one wedging element, and the piston being connected to the other wedging element by a piston rod passing through the said one wedging element; the wedging elements, upon moving axially, being guided by the radially movable expander elements and being oatingly movable radially therewith, and the piston and cylinder being axially and radially movable with the wedging elements to which they are ccnnected.

5. In a machine for expanding and truing up to cylindrical form the metal of a tubular metal body; a frame; a plurality of elongated expander elements disposed in a generally cylindrical series around an axis, and having outer surfaces defining a cylinder, disposed for telescoping of the body thereover; means supporting the expander elements on the frame and guiding them for movement radially toward and from the axis, and independently of each other; stop means for limiting radial movement of the expander elements away from the axis; a pair of tapered Wedging elements disposed within the opposite ends respectively of the cylindrical series of expander elements, for moving the expander elements away from the axis upon movement of the wedging elements axially in opposite directions; a iluid pressure cylinder and a piston therein for moving the wedging elements; the cylinder being connected to one Wedging element, and the piston ybeing connected to the other wedging elementv by a piston rod passing through the said one wedging element; the wedging elements, upon moving axially being guided by the radially movable expander elements, and being floatingly movable radially therewith, and the piston and cylinder being axially and radially movable with the wedging elements to which they are connected; said stop means comprising means for limiting the axial movement of the wedging elements.

6. In a machine for expanding and truing up to cylindrical form the metal of a tubular metal body; a frame; a plurality of elongated expander elements disposed in a generally cylindrical series around an axis, and having outer surfaces defining a cylinder, disposed for telescoping of the body thereover; means supporting the expander elements on the frame and guiding them for movement radially toward and from the axis, and independently of each other; stop means for limiting radial movement of the expander elements away from the axis; a pair of tapered wedging elements disposed within the opposite ends respectively of the cylindrical series of expander elements, for moving the expander elements away from the axis upon movement of the wedging elements axially in opposite directions; a uid pressure cylinder and a piston therein for moving the wedging elements; the cylinder being connected to one wedging element, and the piston being connected to the other wedging element; the wedging elements, upon moving axially being guided by the radially movable expander elements, and being oatingly movable radially therewith, and the piston and cylinder being axially radially movable with the wedging elements to which they are connected.

CHALMER E. MURPHY. 

